Hot answers tagged

22

Neutrinovoltaic panels We can generate pseudo-never-ending power from all sorts of particles impacting all sorts of surfaces. Starting with the most common - visible light photons. Earth-made photo-voltaic panels (aka - solar panels) can last 20+ years, turning photons to power for as long as the panels are in the sun, slowly degrading from UV exposure and ...


20

I think you have some confusion: kinetic energy, in the non relativistic regime, is $K=$$1\over2$$ mv^2$. Momentum is $M=mv$. Neither of them has to do with acceleration. If the mage can remove kinetic energy, it means the velocity (or the mass) is set to 0, and therefore also the momentum goes to 0. For a bullet nullifying its velocity would mean that it ...


19

A black hole with mass of 3.6 million tonnes has a lifetime of 130000 years and will emit $2 \cdot 10^{13}$ W. Slightly increase the mass and you can prolong the lifetime as you please. Then apply the HandyWavy$^{TM}$ stack to convert the Hawking radiation emitted by the black hole into usable energy. Don't forget to put into the balance also the maintenance ...


17

Almost Certainly Not 6 MW is a lot of power, and all of the proposed mechanisms can only sip at available power. (Or wouldn't work at all.) Efficiency As with anything that moves through a medium, most efficiency gains are realized by aero or aqua-dynamics. So a knife-nosed submarine would see more efficient movement forwards, but would have enormous power ...


13

Geothermal power. The ship has extended a long and durable metal spike down 20 km into the upper mantle. Heat is conducted up this spike to the ship, where it powers a Stirling engline on the temperature differential between the mantle and the cool waters where the ship is. The ship came to rest in a place where the mantle was close enough to the surface to ...


12

Can this magic system directly violate the laws of thermodynamics and conservation of energy? There's two halves to this. The energy leaking into the Universe, and the nanites which use it. First the nanites. When you poke a hole in space, random energy flows into it, complex subatomic nanites, that harvest and than manipulate the energy. Whatever energy ...


12

According to this research paper, railguns can be about 47% energy efficient. A 'normal' rifle bullet (Winchester .308 firing and 11 gram bullet) imparts some 3551Joule to the bullet. One energy calculation later: Your railgun requires 3551/0.47 = 7555 Joule total energy per bullet. Slightly more than half of this ends up as waste heat in the device. I'm ...


11

This is a great question, but let's start with the natural limitation In keeping with the laws of thermodynamics, the human body cannot generate more energy (for any purpose, including cooling or heat) than it can take in. In fact, since some of the energy it takes in must be used to keep the body alive, there's a substantial limitation to what the body can ...


10

Aqueducts! Ancient times can has many surprising feats of engineering. Aqueducts are one of these feats of engineering. Look at this one: https://en.wikipedia.org/wiki/Zaghouan_Aqueduct It drops an average of 0,3% it's total length over 90KM (56 miles). This small incline is enough for a continuous water flow. All by careful measurements in an age where ...


10

Both the walls of aqueducts and powerlines exert resistance ...so, the real question should be if this is more efficient than using a high-voltage powerline. Your primary competing product to your canal system would be high-voltage, direct current (HVDC) powerlines which are normally used for transferring power over very long distances. The longest and ...


10

You could use RTG, just as humans do for some of our spaceships. Only you need to select radioisotope which would last longer. Humans have used up to Americium-241, which has half-life of 432 years, but they could use radioisotopes with longer half-life, for example thorium-230 which has half-life of about 75 thousand years. But your power requirements ...


9

Superfluid helium is such only below 2.17 K. This means that, to keep in that condition, you need to continuously remove energy from it, because, you know, practically everything else is hotter than it. And to induce motion into it (the only way to benefit from its superfluidity) you would need to physically insert some sort of paddle in it and that would ...


8

This is probably much less exciting that you make it sound. I don't know what you mean by gap in spacetime or isolating space. But it sounds something like the vacuum energy, where a large area of so called empty space has a small nonzero potential distributed across it. So if you take a cubic mile of space and look at every point at once there is a 0....


8

From the little I know, I know that humans produce electrical charges to contract muscles Your premise is wrong. Electrical pulses in human body do not directly energize muscles, they just carry the signals between the brain and the muscle. The actual energy source is this molecule, called ATP Adenosine triphosphate (ATP) is an organic compound and ...


8

Wind affects the motion of projectile, deviating it from its ideal parabolic trajectory. Drag, which is nothing else that air resistance, also affects the projectile trajectory, shortening it. So, yes, an air flow can disturb the trajectory of a projectile. However it will need long distances to have a noticeable effect, unless the flow velocity is very high....


8

No, unless your incoming projectiles are bubbles or marshmallows. Bullets and missiles have a relatively high velocity. That means that the amount of time you have to deflect with an air-stream them is very small. Consider the frame of reference of a moving bullet. The entire time they are in flight, the air they pass through is effectively a VERY fast wind ...


7

Your most powerful being is going to be small because of the criteria. Small creatures have relatively more surface area compared to the volume of their body, this makes them lose heat much faster than larger creatures. To compensate their metabolic rate (more specifically their mitochondria) is much higher to keep warm. Consequently they need to eat more to ...


7

Antimatter Batteries I think anti matter fits your use-case well. Benefits of Antimatter Very simple to moderate the amount of draw, low minimum power threshold Your energy extraction is directly proportional to the amount of mass you input into the system. Many other power systems like Fusion, Fission, or Hawking Radiation all have minimum output ...


7

He is still figuring it out. It is not like breathing, this power. One or two aspects came easy and then he realized he could do more and he started trying to figure things out. Then a buddy had a suggestion and he has been working on that one. Maybe there are other things too? Leaving his abilities open ended makes for exciting narrative because he ...


7

It seems like you're worried about a problem that's not really a problem. Firstly, black holes take a long time to evaporate... over 575 trillion years at 6x1011kg (for gigawatt luminosity), over 15 million years at 1.8x1010kg (for terawatt luminosity) and over 2600 years at 1x1-9kg( for petawatt luminosity). Secondly, mass loss via Hawking radiation is slow ...


6

According to World Atlas, the highest average metabolic rate on Earth belongs to ruby-throated hummingbirds, who can require up to 7.6 calories per day. https://www.worldatlas.com/articles/which-animal-has-the-fastest-metabolism.html The ruby-throated hummingbird, according to Wikipedia, weighs between 2 and 6 grams. We’ll use 2 grams. Using your own ...


6

Isolate your habitation section from your reactor section Stefan–Boltzmann defines the energy blackbody emissions as: P = AσT⁴ Or for those of us who actually like to know what our variables means: $radiantEnergy = $surfaceArea * 5.67 * $temperature^4; Common logic tells us that the correct course of action is to increase the surface area, and yes, this ...


6

Yes, but they would need to be inconveniently large/long. There is most definitely electrical energy to be had in storms, just look at lightning. The available voltage gradients are quite sufficient, up to 300V per cm. Unfortunately, this electrical energy is present in the form of static electricity, and thus the charge density per volume is very, very, ...


6

Let me start by addressing the issue of magnets. The Large Hadron Collider, for example, requires 1232 dipole magnets generating magnetic fields of 8.3 tesla. I'm a little doubtful that rare earth magnets could achieve this properly; individually, they seem unable to achieve fields of more than ~1 tesla - nor are they capable of maintaining that field far ...


6

No @L.Dutch is correct (and I upvoted his answer), the laws of thermodynamics are in play, assuring that the energy required to maintain the condition for storage will draw away from that storage (if not be in excess of what you could store)... ... but more to the point, it's impossible to store an infinite amount of energy in a finite medium no matter what ...


6

There are lots of possible options. This is not an exhaustive list, but it covers some of the main options: Solid State Thermoelectric generators For lower temperatures (i.e. below the melting point of solid materials), a Thermoelectric generator is your friend. The Seebeck effect is when a voltage generates over a length of material that has a temperature ...


6

Dyson Sphere, hm, no if your prerequisite is energy to matter conversion. It may depend on how much matter they need to satisfy their needs, how many of them there are, and all that. But using 100% of sun energy, in a 100% efficient way - they can make 4 million tons of matter per second. Or about 1.2e14 tons per year. This is a significant number, as mass ...


5

Frame Challenge: Assumptions are being made in the question regarding DNA modification being a kind of magic. Pretty Much a Normal Diet It's a pretty common sci-fi trope, but DNA modification isn't magic. If the DNA in every cell in your body changed to that of a capuchin monkey right now, it would be some time before you noticed anything, and it wouldn't ...


5

Yes, but it's because you made an assumption that's false Truly higher civilizations will try to use the least amount of energy possible, until their energy consumption is as close to zero as possible, which sounds like a neat idea to me but I can't imagine a highly sophisticated and intelligent life-form/civilization running their bodies and technology on ...


5

I was all set to call this idea ridiculous. Then I investigated. Modern water turbines operate at up to 90% mechanical efficiency. Electrical generators can be 90% efficient or more. So, more than 80% of the energy delivered to the generator location could get turned into electrical power. After that, it's the local grid's problem. To make the flow of water ...


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